1. Field of the Invention
This invention pertains generally to paint ball guns used for recreational and training purposes. For the purposes of this disclosure, paint ball guns are specifically defined as apparatus that propel gelatin capsules filled with paint from a barrel in rapid succession and at relatively high speeds. The paint ball capsules are designed to break upon impact with an object or person, thereby rendering an identifiable mark without injuring the person or object. The present invention more specifically pertains to an electronically controlled magazine that stores and feeds paint balls into a firing chamber at enormous rates.
2. Description of the Related Art
Paint ball guns can fire in rapid succession a relatively large number of paint balls in a short period of time. A magazine stores the paint balls until the balls are delivered to the gun firing chamber. The guns use compressed gas as the propellant, and are usually triggered by a user squeezing a conventionally shaped gun trigger. When the gun user repeatedly squeezes the trigger, the gun should continue to fire paint balls as rapidly as possible. Guns may be manually loaded before each shot, but most are either semi-automatic, where each time the trigger is pulled a paint ball is fired, or fully automatic, where the balls are fired as quickly as the gun is capable of for as long as the trigger is pulled.
Quite unlike conventional explosive-propelled munitions, paint balls are relatively round and have an exterior formed from a semi-rigid gelatinous compound. The gelatinous compound is known to be affected somewhat by such variables as temperature and relative humidity, and is of course somewhat frangible. During a firing sequence, paint balls on occasion lodge against each other or other objects and block the passageway to the firing chamber, resulting in a jam. While jamming is not new, knowledge from explosive munitions magazines is of little use with the very different paint balls.
Basic paint ball magazines are little more than large hoppers with a feed tube extending therefrom, a sort of closed funnel through which paint balls are dropped into the firing chamber. Unfortunately, the passageway must ultimately taper to isolate single paint balls therein. Usually this is not a gradual taper, but a sudden transition, to reduce the likelihood of two balls getting stuck against each other. Unfortunately, when one paint ball does lodge against the other, the user must shake the gun to free the balls.
One method of preventing paint ball jams is proposed by Miller in U.S. Pat. No. 5,097,816. Therein, a large helical magazine is provided through which the paint balls pass in a single row, eventually leading to the firing chamber. Unfortunately, the Miller design does not use space efficiently, requiring a large helical path with the center portion thereof unused. The extra dimension is undesirable. Furthermore, because of the reduced slope of the surfaces heading into the firing chamber, actual feed rates may be reduced and paint balls may not be provided at speeds sufficient to meet the needs of the more rapidly firing guns. Cleaning of the Miller construction, which is necessary over time to ensure smooth feeding of the paint balls, is difficult also due to the inaccessibility of the central loops of the helix.
Farrell in U.S. Pat. No. 5,511,333 also illustrates a magazine designed not to jam. Unfortunately, the straight tube design severely limits the number of balls contained within a single magazine. When a rapid fire sequence is initiated, the gun may not jam, but it is highly probably that the magazine will empty, still rendering the gun temporarily disabled.
U.S. Pat. No. 5,282,454 to Bell et al discloses a large magazine with sloping ends and side walls that lead downward to a tubular passageway referred to as a feed tube. Gravitational forces tend to urge the paint balls to the feed tube, as known in the prior art. The magazine is large, capable of holding many paint balls at a time. The feed tube is connected to the firing chamber of the gun, so that as the paint balls are carried through the tube, they are fed into the firing chamber. Occasionally, a pair of paint balls will simultaneously drop into the opening of the feed tube so that neither can pass, leading to a jam.
To prevent jamming of this type, the Bell et al patent proposes an agitator paddle to stir the paint balls. The agitator paddle may slightly overlap the feed tube opening. In addition to directly clearing any jams at the feed tube opening, the agitator paddle also keeps other paint balls within the magazine moving and available for feeding through the tube. If the gun is tilted slightly, the agitator paddle will tend to stir the balls and encourage them to move around, with the increased likelihood that they will continue to pass into the feed tube.
Since the agitator paddle is driven by a small DC motor, batteries are required. Unfortunately, the battery drain is significant. To preserve the battery during periods of non-use, as well as ensure that a user may stay quiet, absent the sounds of the motor and agitator, Bell et al disclose an optical sensor within the feed tube which detects paint balls within the tube. When no ball is present, an electronic circuit triggers the motor to spin the agitator. As soon as a paint ball blocks the optical path, the motor is again stopped.
While the Bell et al design enhances the rate at which paint balls may pass into the feed tube and has enhanced the sport, improved guns and occasional mishaps have revealed limitations therein. First of all, the simple paddle shown in the Bell et al patent, while helpful, still does not ensure sufficient feed rates for some of the newer model guns. To overcome this feed rate limitation, newer designs include higher power motors propelled by twice as many batteries. The standard model agitator is propelled by a single nine volt battery, while the enhanced version is propelled by two nine volt batteries. In addition, the paddle has been redesigned to have four flat surfaces extending longitudinally parallel with the motor shaft and radially therefrom, equidistantly spaced at 90 degree intervals. While this model improves the feed rate significantly, the added weight and cost of the additional battery is certainly undesirable. Furthermore, the added size of the battery compartment makes the gun an easier target for an opponent to hit.
A second limitation of the Bell et al design comes from the occasional, albeit infrequent, breakage of a paint ball. When a paint ball breaks, the optical sensor of the Bell et al design is rendered inoperative, and the sensor must be carefully cleaned.
A third limitation of the Bell et al design is the sensor reacting not to demand from the gun to trigger the agitator, but instead to presence of balls within the feed tube. Consequently, when a rapid fire sequence is initiated, the agitator is slow to start rotating. Furthermore, each time a ball passes through the feed tube, the optical sensor is interrupted, and the agitator stopped momentarily.
Williams, in U.S. Pat. No. 5,505,188 discloses a further alternative. A coiled tube within the magazine chamber is pressurized during the firing process to force balls into the feed tube. During rapid fire sequences, the magazine is certainly agitated by motion of the coiled tube. However, the coiled tube does not positively clear the feed tube opening and so can, in some instances, actually create a jam at the feed tube inlet.